text: An LES filter can be applied to a spatial and temporal field  and perform a spatial filtering operation, a temporal filtering operation, or both.  The filtered field, denoted with a bar, is defined as:
  where  is the filter convolution kernel.  This can also be written as:
  The filter kernel  has an associated cutoff length scale  and cutoff time scale .  Scales smaller than these are eliminated from .  Using the above filter definition, any field  may be split up into a filtered and sub-filtered (denoted with a prime) portion, as
  It is important to note that the large eddy simulation filtering operation does not satisfy the properties of a Reynolds operator.